<div>
    <RadioGroup @bind-Value="radioValue4" ButtonStyle="solid">
        <Radio RadioButton Value="A">Hangzhou</Radio>
        <Radio RadioButton Value="B">Shanghai</Radio>
        <Radio RadioButton Value="C">Beijing</Radio>
        <Radio RadioButton Value="D">Chengdu</Radio>
    </RadioGroup>
</div>
@code
{
    string radioValue4 = "A";
}